# uncompyle6 version 3.2.3
# Python bytecode 3.6 (3379)
# Decompiled from: Python 3.6.8 |Anaconda custom (64-bit)| (default, Feb 21 2019, 18:30:04) [MSC v.1916 64 bit (AMD64)]
# Embedded file name: site-packages\werkzeug\filesystem.py
"""
    werkzeug.filesystem
    ~~~~~~~~~~~~~~~~~~~

    Various utilities for the local filesystem.

    :copyright: (c) 2015 by the Werkzeug Team, see AUTHORS for more details.
    :license: BSD, see LICENSE for more details.
"""
import codecs, sys, warnings

has_likely_buggy_unicode_filesystem = (
    sys.platform.startswith("linux") or "bsd" in sys.platform
)


def _is_ascii_encoding(encoding):
    """
    Given an encoding this figures out if the encoding is actually ASCII (which
    is something we don't actually want in most cases). This is necessary
    because ASCII comes under many names such as ANSI_X3.4-1968.
    """
    if encoding is None:
        return False
        try:
            return codecs.lookup(encoding).name == "ascii"
        except LookupError:
            return False


class BrokenFilesystemWarning(RuntimeWarning, UnicodeWarning):
    """The warning used by Werkzeug to signal a broken filesystem. Will only be
    used once per runtime."""

    pass


_warned_about_filesystem_encoding = False


def get_filesystem_encoding():
    """
    Returns the filesystem encoding that should be used. Note that this is
    different from the Python understanding of the filesystem encoding which
    might be deeply flawed. Do not use this value against Python's unicode APIs
    because it might be different. See :ref:`filesystem-encoding` for the exact
    behavior.
    
    The concept of a filesystem encoding in generally is not something you
    should rely on. As such if you ever need to use this function except for
    writing wrapper code reconsider.
    """
    global _warned_about_filesystem_encoding
    rv = sys.getfilesystemencoding()
    if has_likely_buggy_unicode_filesystem and not rv or _is_ascii_encoding(rv):
        if not _warned_about_filesystem_encoding:
            warnings.warn(
                (
                    "Detected a misconfigured UNIX filesystem: Will use UTF-8 as filesystem encoding instead of {0!r}"
                ).format(rv),
                BrokenFilesystemWarning,
            )
            _warned_about_filesystem_encoding = True
        return "utf-8"
    else:
        return rv
